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Abstract:

Embodiments disclosed herein provide a device for securing a ligature to
an osseous structure, the device comprising a first part, a second part,
a flexible elongate member for engaging the osseous structure, a closure
element, and a deformable element between the first and second parts for
holding open a gap G between them. The flexible elongate member is
threaded through an orifice in the first part and the gap G. The closure
element is configured for clamping the first and second parts against
each other, overcoming the resilience of the deformable element, so as to
frictionally lock the flexible elongate member threaded through the gap
G. Embodiments disclosed herein also provide a method for using the
device.

Claims:

1. A device for securing a ligature to an osseous structure, comprising:
a first part; a second part; a flexible elongate member for engaging the
osseous structure, the flexible elongate member being threaded through an
orifice in the first part and a gap between the first and second parts; a
closure element for clamping the first and second parts against each
other so as to frictionally lock the flexible elongate member threaded
through the gap between the first and second parts; and a deformable
element between the first and the second part, which in an initial,
undeformed position is suited to hold open said gap, and which in a
second, deformed position allows the gap to be narrowed.

2. The device for securing a ligature to an osseous structure according
to claim 1, wherein the deformable element is plastically deformable
between said undeformed and deformed positions.

3. The device for securing a ligature to an osseous structure according
to claim 1, wherein the deformable element is elastically deformable
between said undeformed and deformed positions.

4. The device for securing a ligature to an osseous structure according
to claim 1, wherein the deformable element is solid with the first and/or
the second part.

5. The device for securing a ligature to an osseous structure according
to claim 1, wherein said closure element is screw-threaded.

6. The device for securing a ligature to an osseous structure according
to claim 5, wherein said closure element comprises a shank with an outer
screw thread in engagement with a complementary inner screw thread in one
of the first or second parts, and a head in engagement with the other one
of the first or second parts.

7. The device for securing a ligature to an osseous structure according
to claim 1, wherein the flexible elongate member has a first end and a
second end, and each one of the first end and the second end is threaded
through an orifice in the first part and a gap between the first and
second parts.

8. The device for securing a ligature to an osseous structure according
to claim 7, wherein each one of the first and second ends of the flexible
elongate element is separately threaded through the gap.

9. The device for securing a ligature to an osseous structure according
to claim 8, wherein the first end of the flexible elongate element is
threaded through a first orifice in the first part, and the second end of
the flexible elongated element is threaded through a second orifice in
the first part.

10. The device for securing a ligature to an osseous structure according
to claim 1, wherein the closure element is configured to releasably clamp
the first and second parts against each other.

11. The device for securing a ligature to an osseous structure according
to claim 1, wherein the flexible elongate element comprises a flat band.

12. The device for securing a ligature to an osseous structure according
to claim 1, wherein the flexible elongate element comprises a plurality
of strands.

13. A method for securing a ligature to an osseous structure, comprising:
looping a flexible elongate member around at least part of the osseous
structure; threading the flexible elongate member through a gap between a
first part and a second part and through an orifice in the first part;
tensioning the flexible elongate member, so that the first and second
parts are tightly bound to the osseous structure; and tightening a
closure element between the first and second parts, so as to tighten the
gap between the first and second parts against a resilience of a
deformable element, and frictionally locking the flexible elongate
element in the tightened gap between the first and second parts.

14. The method according to claim 13, further comprising: loosening the
closure element to unlock the flexible elongate member; adjusting a
tension in the flexible elongate member; and tightening the closure
element again to tighten the gap between the first and second parts and
frictionally lock the flexible elongate element again in the tightened
gap between the first and second parts.

15. The method according to claim 13, wherein the flexible elongate
member is threaded twice through the gap between the first part and the
second part.

16. The method according to claim 13, wherein the osseous structure
comprises a spine segment.

17. The method according to claim 16, wherein the osseous structure
comprises a cervical segment.

18. The method according to claim 16, wherein the osseous structure
comprises a thoracic segment.

19. The method according to claim 16, wherein the osseous structure
comprises a lumbar segment.

20. The method according to claim 13, wherein the osseous structure
comprises a rib or a hip bone.

Description:

TECHNICAL FIELD

[0001] Embodiments relate to a device and a method for securing a ligature
to an osseous structure, in particular for reinforcing, or stabilizing
the osseous structure, or for correcting a deformity in the osseous
structure.

BACKGROUND

[0002] In all vertebrate animals, including humans, osseous structures
provide an essential solid framework for the body. Injury, age or disease
may however damage these osseous structures. In order to repair or at
least alleviate such damage, various medical and surgical techniques have
been proposed. In particular, a number of surgical techniques have been
proposed using wire ligatures to reinforce or correct such injured,
diseased, or otherwise damaged osseous structures.

[0003] Surgical wiring techniques have in particular been applied for
treatment of the spine, and more especially of upper cervical fractures
and thoraco-lumbar fractures. For example, the Gallie and Brooks
atlanto-axial stabilization techniques using wires can be used for the
treatment of Type II and III C2 odontoid fractures, i.e., fractures at
the base of the C2 odontoid or transversally to the body of the C2
vertebra; as well as Type III C2 traumatic spondylolisthesis, i.e., C2
"hangman fractures" with severe displacement and angulation. The Wertheim
and Bohlman occipitocervical stabilization technique can be used for the
treatment of fractures of the closed ring of the C1 vertebra, as well as
for the stabilization of the C1-C2 segment when affected by rheumatoid
arthritis.

[0004] Trauma, such as distractive flexion injuries with facet disruption
and dislocation, or ligamentous injuries, to other cervical segments, for
instance at the C5-C6 level or at the fulcrum between cervical and
thoracic spine, can be treated using subaxial cervical stabilization with
such wiring techniques as the Rogers technique, the Bohlman triple wire
technique, the Dewar technique, or the Robinson and Southwick facet
wiring technique.

[0005] Finally, among the thoraco-lumbar fractures that can be reduced and
stabilised using wiring techniques, and in particular Harrington rods
with sublaminar wires and interspinous wires, are compression fractures,
flexion distraction fractures ("seatbelt fractures"), and dislocated
fractures.

[0006] However, the metallic wires used in such wiring techniques present
some drawbacks, in particular with respect to biocompatibility, strength,
stability and material fatigue, and stress concentrations where they
contact the bones. Even more significantly, adjusting the wire tension
while tying the wire requires very high dexterity, and may be even more
difficult once the wire is tied.

[0007] In the prior art, it has also been proposed to use flexible
elongated elements other than wires to tie various implants to underlying
osseous structures. In particular, intervertebral implants have been
proposed which are tied to the vertebrae using flat bands, for instance
in International Patent Application publication WO 2009/040380. Such flat
bands have the advantages of higher biocompatibility, strength and
stability, as well as better stress distribution on the bones. While
adjusting the band tension remains difficult, this is less critical in
this application, since the main stresses go through the body of the
intervertebral implant, rather than the flat band.

SUMMARY

[0008] A first object of the disclosure is that of providing a device for
securing a ligature to an osseous structure, wherein the tension in the
ligature can be more easily adjusted than with previous devices and
methods.

[0009] Accordingly, a device for securing a ligature to an osseous
structure according to at least one illustrative embodiment of the
disclosure comprises a first part, a second part, a flexible elongate
member for engaging the osseous structure, the flexible elongated member
being threaded through an orifice in the first part and a gap between the
first and second parts, a closure element for clamping the first and
second parts against each other so as to frictionally lock the flexible
elongate member threaded through the gap between the first and second
parts, and a deformable element between the first and the second part,
which in an initial, undeformed position is suited to hold open said gap,
and which in a second, deformed position allows the gap to be narrowed.

[0010] Because the deformable element holds the gap open in its undeformed
position, the flexible elongate element remains free to slide through the
gap, and the tension of the flexible elongate element can be easily
adjusted without having to simultaneously hold the first and second parts
apart from each other. The first and second parts can nevertheless be
subsequently clamped against each other using the closure element,
deforming the deformable element so that the gap is narrowed, and
frictionally locking the flexible elongate member within this gap between
the first and second parts.

[0011] The deformable element may be plastically or elastically deformable
between said undeformed and deformed positions, wherein an elastically
deformable element can provide an advantage of recovering its function of
holding open the gap between the first and second parts if the closure
element is subsequently released. On the other hand, a plastically
deformable element may be more easily provided, and at a lower cost.

[0012] In some embodiments, the deformable element is solid with the first
and/or the second part, reducing the number of separate parts of the
device, thus simplifying both its production and operation and reducing
the risk of incorrect assembly.

[0013] In some embodiments, the closure element is screw-threaded. In
particular, said closure element may comprise a shank with an outer screw
thread in engagement with a complementary inner screw thread in one of
the first or second parts, and a head in engagement with the other one of
the first or second parts. Consequently, the first part and the second
part can easily be clamped against each other by tightening the closure
element.

[0014] In some embodiments, the flexible elongate member has a first end
and a second end, and each one of the first end and the second end is
threaded through an orifice in the first part and a gap between the first
and second parts. Consequently, both ends of the flexible elongate member
can be simultaneously locked by closing the first part and the second
part against each other.

[0015] Among some of these embodiments, each one of the first and second
ends of the flexible elongate element is separately threaded through the
gap. In particular, the first end of the flexible elongate element may be
threaded through a first orifice in the first part, and the second end of
the flexible elongated element may be threaded through a second orifice
in the first part. The first and second ends of the flexible elongate
element can thus be laterally offset with respect to each other,
providing a more versatile ligature.

[0016] In some embodiments, the closure element is configured to
releasably clamp the first and second parts against each other. The first
and second parts could thus be released from each other after being
clamped against each other, thus allowing a readjustment of the tension
in the flexible elongate member.

[0017] In some embodiments, the flexible elongate member may comprise a
flat band or a plurality of strands, in particular arranged side-by-side.
Consequently, the stresses transmitted by the band or strands to the
osseous structure are distributed over a wide area, preventing further
damage to the bone structure.

[0018] Another object of the disclosure is that of providing an easier,
safer method of securing a ligature to an osseous structure.

[0019] Accordingly, in at least an illustrative embodiment of the
disclosure, a method for securing a ligature to an osseous structure
comprises the steps of looping a flexible elongate member around at least
part of the osseous structure, threading the flexible elongate member
through a gap between the first part and the second part and an orifice
of the first part, tensioning the flexible elongate member, so that the
first and second parts are tightly bound to the osseous structure, and
tightening a closure element between the first and second parts, so as to
tighten the gap between the first and second parts against a resilience
of a deformable element, and frictionally locking the flexible elongate
element in the tightened gap between the first and second parts.

[0020] Because the resilience of the deformable element has to be overcome
to tighten the gap and lock the flexible elongate member, the tension in
said flexible elongate member remains easily adjustable until the closure
element is actively operated, against the resilience of said deformable
element, to clamp the first and second parts against each other.

[0021] In some embodiments, the flexible elongate member is threaded twice
through the gap between the first part and the second part, so that both
ends of the flexible elongate member can be frictionally locked by the
tightening gap when the closure element is operated to close the first
and second parts against each other.

[0022] In some embodiments, the osseous structure comprises a spine
segment. In particular, it may comprise a cervical segment. The method
according to the disclosure may be used, for instance, to treat Type II
and III C2 odontoid fractures or Type III C2 traumatic spondylolisthesis
with an upper cervical ligature according to the Gallie and Brooks
atlanto-axial stabilization techniques. It may also be used for the
treatment of fractures of the closed ring of the C1 vertebra, as well as
for the stabilization of the C1-C2 segment when affected by rheumatoid
arthritis, with an upper cervical ligature according to the Wertheim and
Bohlman occipitocervical stabilization technique. Trauma to other
cervical segments, such as distractive flexion injuries with facet
disruption and dislocation, or ligamentous injuries, for instance at the
C5-C6 level or at the fulcrum between cervical and thoracic spine, may be
treated with a ligature to a corresponding spine segment following a
known subaxial cervical stabilization technique. It must be understood
that, although those techniques conventionally apply wires, according to
the method a flat band or a plurality of strands may be tied to the
osseous structure analogously to those wires, which has the additional
advantage of distributing the contact stresses over wider areas of the
bones.

[0023] The osseous structure may however also comprise a thoracic or
lumbar segment. The method according to the disclosure may for instance
be used to stabilise a thoraco-lumbar segment in case of a compression
fracture, flexion distraction fracture, or dislocated fracture.

[0024] The method according to the disclosure may even be used to secure a
ligature to other osseous structures than the spine, such as e.g. long
bones, to secure implants and/or treat fractures. For instance, this
method may be used for providing a rod-less arthrodesis, or for
stabilizing a hip bone by trochanteric fixation using, for example, the
Dall-Miles technique, or in hip revision surgery to prevent vessel
necrosia or for a complementary rib ligature exerting a lateral rib
traction for scoliosis correction.

[0025] The above summary of some example embodiments is not intended to
describe each disclosed embodiment or every implementation of the
invention. In particular, selected features of any illustrative
embodiment within this specification may be incorporated into an
additional embodiment unless clearly stated to the contrary.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The disclosure may be more completely understood in consideration
of the following detailed description of various embodiments in
connection with the accompanying drawings, in which:

[0027]FIG. 1 is a perspective view of a device according to a first
embodiment;

[0032] FIGS. 6A and 6B show detail cut views of the device of FIG. 1
through the same plane V-V, at successive stages of its operation to
secure a ligature;

[0033]FIG. 7 shows a detail cut view of the device of FIG. 1 through
plane IV-IV when the ligature is secured;

[0034]FIG. 8 shows a section of a flexible elongate element of a device
according to a second embodiment; and

[0035]FIG. 9 shows a number of potential positions in a human skeleton
for a ligature secured with the device of FIG. 1.

[0036] While the embodiments are amenable to various modifications and
alternative forms, specifics thereof have been shown by way of example in
the drawings and will be described in detail. It should be understood,
however, that the intention is not to limit aspects of the invention to
the particular embodiments described. On the contrary, the intention is
to cover all modifications, equivalents, and alternatives falling within
the scope of the claims.

DETAILED DESCRIPTION

[0037] For the following defined terms, these definitions shall be
applied, unless a different definition is given in the claims or
elsewhere in this specification.

[0038] As used in this specification and the appended claims, the singular
forms "a", "an", and "the" include plural referents unless the content
clearly dictates otherwise. As used in this specification and the
appended claims, the term "or" is generally employed in its sense
including "and/or" unless the content clearly dictates otherwise.

[0039] The following detailed description should be read with reference to
the drawings in which similar elements in different drawings are numbered
the same. The detailed description and the drawings, which are not
necessarily to scale, depict illustrative embodiments and are not
intended to limit the scope of the invention. The illustrative
embodiments depicted are intended only as exemplary. Selected features of
any illustrative embodiment may be incorporated into an additional
embodiment unless clearly stated to the contrary.

[0040] A device 10 for securing a ligature to an osseous structure
according to a first embodiment is shown in FIGS. 1 and 2. In this
particular embodiment, the device 10 is disc-shaped, which is an
advantageous shape for its ease of handling and unobtrusiveness once
implanted, but other alternative shapes may also be considered. This
device 10 comprises a first part 11 and a second part 12 linked by a
closure element 13 in the form of a screw with a screw-threaded shank 13a
in engagement with a complementarily screw-threaded orifice 14 in the
second part 12, and a head 13b in engagement with a recess 15 in the
first part 11. Guiding blocks 16 protruding laterally from the second
part 12 engage corresponding recesses 17 in the first part 11 to suppress
rotation between the first and the second parts 11,12, while still
allowing their translation, relative to each other, along the
longitudinal axis X of the screw 13.

[0041] The device 10 also comprises a flat, flexible band 18 adapted to
form a ligature to an osseous structure. This band 18 is made of a
biocompatible material, in particular comprising synthetic materials such
as, but not limited to, polyester, polyethylene terephtalate (PET),
ultra-high-molecular-weight polyethylene (UHMPE), or polyetheretherketone
(PEEK).

[0042] While this first embodiment of the device 1 comprises a flat band
18, other types of flexible elongate members may alternatively be used
for the ligature. For instance, in a second embodiment, a plurality of
separate, substantially parallel strands 18', as illustrated in FIG. 8,
could be used in place of the flat band of the first embodiment. The
other parts of the device for securing this ligature to an osseous
structure could be substantially equivalent to those of the first
embodiment, and the device could be used analogously.

[0043] Turning back to the first embodiment, each end 18a, 18b of the band
18 is threaded through one orifice 19 in the first part 11, and a gap G
between the first part 11 and the second part 12, as can be seen in
particular in FIGS. 3 and 4. As illustrated in FIG. 5, deformable,
wing-shaped elements 20 protruding from each block 16 initially maintain
this gap G, holding the bodies of the first and second part 11, 12 apart
from each other.

[0044] In use, the width of the gap G initially maintained by the
deformable elements 20 allows the band 18 to slid through the gap G and
the orifices 19. Consequently, a user can easily make a ligature to an
osseous structure using the band 18, and adjust the tension of the band
18 before securing this ligature. To secure the ligature the screw 13 is
tightened in the orifice 14. Longitudinally guided by the blocks 16 in
the recesses 17, the first and second parts 11, 12 will approach each
other, progressively overcoming the resilience of the deformable elements
20 and bending them, as seen in FIG. 6A and FIG. 6B, until arriving to a
deformed position in which the gap G is so tightened that the first and
second parts 11, 12 clamp around the band 18, as seen in FIG. 7,
frictionally locking the band 18, and thus securing the ligature.

[0045] The screw 13 may be subsequently loosened again to readjust the
band 18. If the deformable elements 20 have only been elastically
deformed, they will return to their initial position illustrated in FIG.
5, holding the gap G open again. However, they will normally have been
plastically deformed and will not return to their initial position. For a
simple readjustment of the band 18, this will nevertheless not constitute
a significant drawback for the user.

[0046]FIG. 9 illustrates several possible locations, in a human skeleton,
for a ligature secured with the device 1. For instance, the ligature may
be located in the upper cervical segment C1-C2 for the treatment of Type
II and III C2 odontoid fractures, Type III C2 traumatic
spondylolisthesis, fractures of the closed ring of the C1 vertebra, or
for the stabilization of the C1-C2 segment when affected by rheumatoid
arthritis. Such a ligature may also be used in the treatment of trauma to
other cervical segments, such as distractive flexion injuries with facet
disruption and dislocation, or ligamentous injuries, for instance at the
C5-C6 level or at the fulcrum C7-T1 between cervical spine C and thoracic
spine T, or to stabilise a segment of the thoracic spine T or lumbar
spine L in case of a compression fracture, flexion distraction fracture,
or dislocated fracture. The ligature may also might be applied also on
other bony structures, such as e.g. long bones, to secure implants and/or
treat fractures. It may, for instance, be used to stabilise a hipbone H,
to exert a traction between ribs R, or to block any suitable joint by
arthrodesis without rods.

[0047] Those skilled in the art will recognize that the invention may be
manifested in a variety of forms other than the specific embodiments
described and contemplated herein. Accordingly, departure in form and
detail may be made without departing from the scope of the invention as
described in the appended claims.